The studies described in this grant application cover the preparation and testing of lymphokine fractions derived from a continuous cultured human lymphoblast cell line, RPMI 1788. During the ensuing year, efforts will be made to refine two new assays which have greatly helped in quantitative evaluation of biological activity and in evaluating patient response. The first is a phagocytic assay involving the uptake of fluorescent beads in peripheral blood neutrophils. The second is an assay of NK cells in peripheral blood, utilizing mouse L1210 tumor cells as targets.